Joint production of solvents and wood preservatives



July 28, 1942- J. E. HARVEY, JR 2,291,305

JOINT PRODUCTION OF SLVENTS AND WOOD PRESERVATIVES Fileld Aug. 14, 1940 M000 PREJMI/Ar/Vfj @f @MW Patented July 28, 1942 UNITED STAT ES TT OFFICE J OINT PRODUCTION OF SOLVENTS AND WOOD PRESERVATIVES Application August 14, 1940, Serial No. 352,666

4 Claims.

The present invention relates to the joint production of rened solvents and wood preservatives from hydrocarbons, said hydrocarbons being characterized by content of oxygenated `co-mpounds and sulfur.

Another object of the present invention is the joint production of refined solvents and wood preservatives from tars of aromatic content and fractions thereof characterized by content of oxygenated compounds and sulfur, under conditions that induce no substantial percentage of fractions of low solvency or low toxicity, or, stated in another manner, under `conditions so controlled as to induce no substantial ,percentage of liquid chain structures or other liquids of relatively low solvency or toxicity that would :preclude the production of the solvents and wood preservatives of the present invention.

Another object of the invention is the joint production of rened solvents and wood preservatives of superior solvency and added toxicity under conditions that induce no substantial percentage of carbonaceous deposition, as for instance coke.

Other objects of the present invention will be apparent from the following disclosures.

The invention will be understood from the following description of illustrative steps comprising various methods o-f securing the objects of the invention, when read in connection with the accompanying drawing wherein the gure is a diagrammatic sketch of an apparatus for carrying out a form of the yprocess of the invention and wherein the nature of the step carried out in each chamber and the contents thereof are indicated by legend.

Example 1.-A coal tar creosote, coke residue 2%, specific gravity 1.08, 35% residue above 355 C. and having content of oxygenated compounds and sulfur is subjected to the action of hydrogen at 350 C. and 200 atmospheres pressure for such a length of time as to reduce sulfur content, thereby lowering corrosivity, or at least providing for lowered corrosivity in iinal poduct. The creosote of lowered sulfur content is passed through a high pressure reaction vessel while simultaneously flowing hydrogen therewith at `a temperature of 400 C. and 200 atmospheres pressure. The catalyst is molybdenum oxide and ammonium chloride. The ow of hydrogen is 12,000 cubic feet .per barrel creosote and the time of contact one hour. The beneciated creosote flowing from the reactor is inspected and will be found to have superior solvency and toxicity and the coke residue, Specific gravity and viscosity will be reduced. No substantial percentage of liquid chain Structures or kindred material will be induced so as to .preclude induction of toxicity. There will be no .appreciable deposition of `carbon in the reaction chamber. The vbeneiiciated creosote is distilled to an upper limit of 270 C. with the distillate serving as the solvent of the present invention having lowered corrosivity and superior solvency; the residue serving as the wood preservative of added toxicity.

By the term superior solvency or enhanced solvency is meant that the solvent or solvents so described are superior in solvency to solvents currently on the market; by the term added toxicity or superior toxicity is meant among other things that the Wood preservatives so described have a toxic value in excess of the .parent material or a cut of comparable initial boiling point on parent material.

The point of fractionation between the solvent and Wood preservative is not inflexible inasmuch as commercial solvents currently on the market have varied end points and wood preservatives of current usage have varied initial boiling points. Thus, inasmuch as the end point of the solvent of the present invention substantially corresponds to the initial boiling point of the wood preservative of the present invention, it -will :be immediately obvious that the point of fractionation is not inflexible, but may be varied at will.

By the eiect of the presence of the catalytic material selected from the group consisting of halogens, halids, and derivatives thereof including substitution and addition products thereof, the decomposition of oxygenated compounds contained in the starting material while under the action of hydrogen, is influenced, thereby enhancing the induction of solvency and toxicity of the present invention.

In the tabular data shown below are solvents and Wood preservatives of accepted specifications, their end points and initial boiling point respectively.

SoLvEN'rs (Identification: End point, C.

Benzol 120 'Ioluol 150 High ash naphtha 200 Heavy naphtha Above 200 WooD PRESERVATIVES Specifications 1. A. W. P. A.:

a. Up to 210 C., not more than 5% b. Up to 235 C., not more than 25% A. W. P. A.:

a. Up to 210 C., not more than 1% bi. Up to 235 C., not more than 10% c. Up to 355 C., not less than 65% 3. A. W. P. A.:

a. Up to 235 C., not more than 11/% b. Up to 300 C., not more than ll/2% c. Up to 355 C., not less than 45% A. W. P. A.:

a. Up to 210 C., not more than 8% b. Up to 235 C., not more than 35% A. W. P. A.:

a. Up to 210 C., not more than 10% b. Up to 235 C., not more than 40% A. W. P. A.:

a. Up to 210 C., not more than 5% b. Up to 235 C., not more than 15% Prussian Ry.: Y

a. Up to 150 C., not more than 3% bi. Up to 200 C., not more than 10% c. Up to 235 C., not more than 25% N. P. V. & L. A. #220:

a. 5% at 162 C. b. 97% at 270 C. 9. S. P. S. S. O.:

a. 5% at 137 C. bi. 95% at 257 C. 10. N. S. S. O.:

a. I. B. P., 150 C. b. 5% at 205 C. c. 95% at 292 C. 11. Carbolineum, 270 C., I. B. P.

The abbreviations used in the foregoing are explained as follows: A. W. P. A., American Wood Preservers Association; N. S. S. 0.,Nev'ille VShingle Stain Oil; S. P. S. S. O., Southern Pine Shingle Stain Oil.

Among other things, the present process is adapted yto provide treatment of tars Vof aromatic content and Vfractions thereof characterized by content of oxygenated compounds'an'd sulfur, with hydrogen as lheretofore described whereby to provide a newly induced low boiling point which substantially comprises if desired the initial boiling point 'of the refined solvent of lower corrosivity and may b'e controlla'bly held at any point to provide substitutes for the boiling range or ranges of any of the following:

or, solvents of special nature may be produced,

as for instance having lower boiling points than above listed.

ciated material is determined by intensity of process controls. Controls of lesser intensity produce higher initial boiling points and controls of greater intensity produce lower boiling points.

Exam-ple 2.-A coal tar, specific gravity 1.1641, a coke residue of in excess of 5% and characterized by content of oxygenated compounds and sulfur is subjected to the action of hydrogen at 375 C. and 200 atmospheres pressure whereby to lower corrosivity or at least providing for lowered corrosivity in a finally processed product; the material of lowered sulfur content is passed through a high pressure reaction chamber while simultaneously flowing hydrogen therewith at a temperature of 400 C. and a pressure of 300 atmospheres. The ow of hydrogen is 12,000 cubic feet per barrel feed stock and the time of contact substantially one hour and a half. The

The initial or low boiling point of the benecatalyst is molybdenum oxide and iodoform. The beneficiated material is found upon inspection to have superior solvency and toxicity; the beneciated material will be further characterized by reduction of coke residue, specic gravity and viscosity. The beneciated material is distilled to an upper limit of C. `to recover the distillate as a, rened solvent of lower corrosivity, and the residue therefrom as a wood preservative of added toxic value.

The term coal tar as used herein means tar produced by high temperature carbonization of coal, as for instance, high temperature coke oven tar or gas house tar.

Example 3.-A coal tar fraction, initial 'boiling 225 C. and having substantially 50r percent residue above 355 C. and characterized by content of oxygenated compounds and sulfur is subjected to the action of hydrogen while contacting a molybdenum sulde catalyst at 380 C. and a pressure of 225 atmospheres to reduce sulfur content whereby to lower corrosivity. The tar fraction of reduced sulfur content is subjected to the action of hydrogen at 400 C. and V300 atmospheres pressure for a period of 65 minutes. The catalyst is cobalt oxide and tin chloride. The beneficiated material flowing from the reactor will be found to have superior solvency and toxicity, and will be further characterized by reduction of coke residue, specic gravity and viscosity. The beneciated material is distilled to an upper limit of 200 C. to provide the distillate as a rened solvent of lowered corrosivity and the residue as a wood preservative of .added toxicity.

Instead of recovering the wood preservative as a residue incidental to the distillation recovery of the solvent both the solvent and the Wood preservative may be recovered as distillates, with the residue being used as an article of commerce, as for instance a binder, plasticizer or the like, or the residue may be recycled.

In the event the intermediate starting material of the reiined solvent of lowered corrosivity is taken by a deep cut on the benel'iciated starting material the higher boiling fractions oi said deep cut, after nal processing, may serve as substitutes for certain plasticizing oils.

Catalysts of the present invention are oxides and the material selected from .the group consisting of halogens, halids, and derivatives thereof 'including substitution and addition products thereof. Oxides of metals of the sixth and eighth periodic groups are usable; the oxides of other groups are usable, however, dicultly revducible oxides are preferred.

Reaction conditions in the initial step that lowers corrosivity by the action of hydrogen may be chosen from a wide range of temperatures and pressures inasmuch as sulfur reduction occurs at lowered temperatures and pressures. The lower limit cf temperature and pressure is advisably that temperature and pressure which effects said reduction in a commercial' manner, that is to say, as regards time element; pressures as high as practicable may be used, and the upper limit of temperature is defined as that temperature which causes under conditions of the process, no substantial deposition of carbon, as for instance coking.

The rst step of hydrogen action may be carried on in a high pressure bomb, or in a continuous manner in a reaction chamber or several reaction chambers and in the event of continuous practice the hydrogen flow is preferably maintained so as to induce no substantial carbon deposit, as for instance coking. In the second cycle of hydrogen action, fiows of in the order of 8,000-15,000 cubic feet per barrel feed have proven satisfactory, however, higher or lower flows may be used, the high and low limits thereof being defined as those flows that induce no unclesirable coking.

By the ter-m beneciated as used herein and in the appended claims is meant the starting material at least once subjected to the action of hydrogen in accordance with the present process.

Starting materials consist of tars of aromatic content and fractions thereof characterized by content of oxygenated compounds and sulfur, and capable of having toxicity induced therein, and materials previously subjected to the action of hydrogen are suitable.

Starting materials of the present process also include tars of aromatic content from which low boiling fractions have been removed, as for instance tars from which solvent oils have been removed. Viewed broadly, the starting materials of the present process are tars of aromatic content, fractions of said tar more viscous than the starting material due to removal of low boiling fractions from the starting material, high boiling fractions and pitches.

The term pitch as used herein includes the higher boiling fractions of tar, in other words, tar from which low boiling ends have been stripped, such low ends being suitable for use per se as creosote, other wood preservative, or solvent. For instance, the final residue resulting from evaporating tar to dryness and then stripping wood preservative from the distillate is a very suitable pitch for use as a starting material of the pres-ent process.

The present invention is predicated on, among other things, so controlling hydrogen action that no substantial percentage of liquid chain structures or kindred materials are induced that would preclude aforesaid solvency and toxicity induction.

The second cycle of hydrogen action may be practiced at lowered pressures and temperatures however, pressures of in the order of 200-400 atmospheres are preferred but high or lower pressures may be used. Temperatures of in excess of 300 C. are preferred, however, lower temperatures may be used; the upper limit of usable temperatures being defined by that temperature which causes no inordinate ccking action.

Some of the starting materials in which toxicity may be induced in accordance with the present 'invention may contain high molecular complexes that are especially susceptible to thermal degradation; these materials may have solvency and toxicity induced therein while higher pressures obtain with the added benefit that such molecular complexes are reduced to a greater extent, thereby enhancing toxicity induction.

The time element of the second cycle of hydrogen action is not circumscribed by any definite time limit, but is merely that period necessary to show superior solvency and toxicity; using some starting feeds periods of 30 minutes or less will result in superior solvency and toxicity. Periods of one hour or longer -may be used.

In the first cycle of hydrogen action that reduces sulfur content, said reduction of sulfur may be accomplished in the presence of a catalyst. Catalyst effective in the presence of hydrogen are usable, as for instance the oxides and/or suldes of molybdenum, vanadium, uranium, cobalt, tin, manganese, tungsten, or the like.

In the disclosures herein made the removing of low boiling fractions by gas movement or pressure release is considered the equivalent of distillation.

When reference is made to high molecular complexes contained in the starting material, and when the starting material contains low boiling fractions that are not considered high molecular complexes, it is of course obvious that the high molecular complexes contained in the starting material are to a certain extent depolymerized by the solvent present.

A convenient method for testing solvency is by evaluating the well-known Kauri-butanol number. Toxicity may be evaluated in accordance with Method of conducting the tests, page 2, technical bulletin No. 346, March, 1933, United States Department of Agriculture.

It will be seen that by reduction of sulfur content of the material under treatment during any stage of hydrogen action, the oxide catalyst used during subsequent stages is at least partially protected from the effect of the sulfur.

Minor changes may be made within the scope of the appended claims without departing from the spirit of the invention.

I claim:

1. In the joint production of solvents and wood preservatives, the process which comprises: subjecting a mixture of sulfur-bearing high temperature coal tar fractions to the sulfur reducing effect of hydrogen whereby to reduce sulfur content in said material; thereafter subjecting said sulfur-refined material to the further action of hydrogen in the presence of an oxide catalyst and additional catalytic material selected from the group consisting of halogens, halids and derivatives thereof including addition and substitution products thereof with temperature and pressure so controlled as to reduce coke residue, specific gravity and viscosity; carrying on the process for such a length of time as to provide a beneciated material from which may be fractionally recovered a relatively low boiling solvent and a relatively high boiling oil of the wood preserving type having induced toxicity and conforming in boiling range according to specifications accepted in the trade for a tar derived wood preservative, and further characterized by a substantial residual above 325 C.; and fractionating the beneciated material to provide said relatively low boiling solvent and said relatively high boiling oil of the wood preserving type.

2,; The process of claim 1 in which the oil of; wood' preserving type isa di*stillate.4

3;. In the joint production of solvents and Wood preservatives, the process which comprises; subjecting av mixture of` sulfur-bearing high temperature coal tar fractions to the sulfur-reduc-V ing action of hydrogen atj a temperature; not substantially less than; 3,50o C.; thereafter subjecting saidI sulfur rei-ined material to the action of a ioW- of hydrogen not substantially less than 8,000, cubic feet per barrel feed stock in the presence of an oxide, catalyst and additional catalytic material selected from the group consisting of halogens, halids andderivatives thereof, including addition and substitution products thereof at aY temperature and pressure not substantially less than 300 C. and 200 atmospheres, respectively whereby to lower coke residue. specific gravity and viscosity.; carrying on the process for such a length of time as to provide a beneficiated material from which may be fractionally recovered a relatively low boiling solvent and a relatively high boiling oil of the Wood preserving type havingV inducedtoxicity and conformingin boilingrange according to specifications accepted in the trade for a tar-derived woodI preservative, and further characterized by a substantial residual above 325 C.; andv fractionating the beneciated material to provide said relatively 10W boiling solvent and said relatively high boiling oil of the wood preserving type.

4. The process of claim 3 in which the oil of Wood preserving type is a distillate..

JACQUELIN E. HARVEY, JR. 

